"I Knew You When" is a song recorded by Canadian pop rock band Marianas Trench.

[6][7] Lead singer Josh Ramsay spoke to Substream Magazine on the meaning behind the song.

Not about drunken lust, or doing shots in a bar, or 'living life for just tonight,' but the kind of real-life relationship that takes a decade to build, through ups and downs.

If I've learned one thing in my life as a performer it's this; if you're going to sing a song every night for the rest of your career, you better mean it – and I do.

[9] The music video for "I Knew You When" was released on YouTube on December 19, 2018 and was directed by Kyle Davison.